Heating devices, especially for motor vehicles



3,078,838 HEATING DEVICES, ESPECIALLY FOR MOTOR VEHICLES Ernst Reinhold Albert Friedrich Broecker, Flen, Sweden,

assignor to Aktiebolaget Bahco, Stockholm, Sweden,

a corporation of Sweden Filed Apr. 26, 196i, Ser. No. 105,813 Claims priority, application Sweden May 6, 1960 4 Ciaims. (Cl. 126-110) The present invention relates to improvements in or relating to heating devices, especially for motor vehicles, and driven by volatile fuels such as gasoline. The device is of the type which comprises a combustion chamber for combustion of the volatile fuel, an electrically driven pump for supplying the fuel, an electrically actuated electromagnetic valve for controlled delivery to the combustion chamber of the fuel supplied by the pump, an electrically heated glow body for igniting the fuel in the combustion chamber, a heating system around which the combustion products from the combustion of the fuel are passing for heating a heating medium, such as air, which is passed through the heating system, an electrically driven fan blower for propelling the heating medium, and two thermostatic switches, with one switch placed adjacent the glow body and actuatable to a different contact position when the glow body has been heated sufiiciently for volatilizing and igniting the fuel, and with the other switch positioned in the heating system and actuatable to a different contact position when the heating medium has attained a predetermined maximum temperature, and with a current source for energizing the pump, the electromagnetic valve, the glow body and the fan blower.

The object of the present invention is to provide a device which is reliable and takes very little current, these characteristics being very important in connection with automatic heating devices which at least partially take their power from a battery, for example a car battery. During the winter there is a great need for attaining in a reliable and cheap way an automatic heating of the interior of a car and/or of the motor and the present invention concerns especially a device for this purpose. It is known earlier to, attain an automatic starting of a heat ing device for a car for example by means of a time relay, but these known arrangements have either been diflicult to fabricate and too complicated to use or have taken too much current from the battery and have therefore not come into common use.

The device according to the present invention, which is designed with due regard to the said desirable features, is especially characterized by the fact that the electromagnetic valve'and the fan blower are dimensioned in such a way that they,.when they by means of one or both of the thermostatic switches directly or indirectly and possibly by means of further elements (for example a timer) are connected to the current source, operate in such a way that there is attained as well opening of the electromagnetic valve and starting of the non-rotating fan blower, when the electromagnetic valve and the fan blower are connected in series to the current source without any further elements of substantial resistance connected in the circuit as also continued opening of the electromagnetic valve when the fan blower after the start has attained normal speed by the said connection of the electromagnetic valve and the fan blower to the current source.

The dimensioning is further preferably such that the electromagnetic valve is not being opened when the electromagnetic valve in series with the fan blower and with the lastnamed rotating with substantially normal speed is connected to the current source without any further elements of substantial resistance connected in the circuit.

A detailed description of the present invention is given 3,978,838 Patented Feb. 26, 1953 in connection with the attached drawing, where FIGURE 1 is a schematic circuit diagram for the device; FIGURE 2 is a time diagram for the functioning of the dilferent units in the device and FIGURE 3 is a diagrammatic view of the combustion chamber with the various components.

In a combustion chamber for burning a volatile fuel, for instance gasoline, there is positioned an electrically heated resistive member formed into a body Ga glow spiralwhich is a resistance heating means and has a terminal connected to ground and the other terminal connected to a stationary contact in a switch b1. For delivery of fuel there is provided an electrically driven pump P, with one terminal connected to ground and the other terminal connected to a moving contact in a switch b2-b3. When the moving contact is in its left position the contact [)3 is open and the contacts bl and 112 are closed, so that the glow body G as well as the pump P via a fuse 25A are connected to the positive pole of a battery E which has its negative pole connected to ground. When the moving contact is in its right position (as seen in FIGURE 1) the contacts bl and b2 are open and the contact b3 is closed, so that the pump P is connected to a stationary contact in a switch at. For a controlled delivery to the combustion chamber of the fuel supplied by the pump P there is an electrically operated electromagnetic valve V which has one terminal connected to a stationary contact in a switch 01 and has the remaining terminal connected to ground via an electrically driven fan blower M which is used for propelling a heating medium, for instance air, with one terminal of the fan blower connected to ground. The remaining terminal of the fan blower M is also connected to a stationary contact in a switch 02, and the moving contact in the switch 02 is at the same time a moving contact in the switch 01 and is connected to the stationary contact in the switch b3. When the said moving contact is in its left position the fan blower M and the electromagnetic valve V are series connected, and when the said moving contact is in its right position (the position shown in FIGURE 1) only the fan blower M is connected between ground and the stationary contact in the switch a1. There are also two thermostatic switches, with one of these, T1, positioned adjacent the glow body G and provided for closing a first circuit, which goes from ground to the positive pole of the battery E, when the glow body G has attained suflicient high temperature for volatilizing and igniting the fuel, and with the other thermostatic switch, T2, provided in a heating system the heating medium, for instance air, going through the heating system, with said second thermostatic switch used for breaking a second circuit from ground to the stationary contact in a switch a1 when the heating medium has attained a predetermined maximum temperature. The switch all is an element in a timer U and has a moving contact connected to a terminal of a winding of a relay 0 and to a terminal of a winding of a relay b. The switches b1, b2 and b3 are elements of the said relay b. The switches 01 and 02 are elements of the said relay c. The switch a1 and a switch a2, which has a stationary contact connected to the remaining terminal of the winding of the relay b and also has a moving contact which also is an element of a switch all, are elements of a relay a, with the winding of the said relay a connected between a moving contact in the thermostatic switch T1 and the common moving contact for the switches a1 and a2.

The device which has been described in detail operates as follows: In the idle position all of the relay switches have the contacts in the positions shown in FIGURE 1, the glow body G is cold, the fan blower M and the pump P are not operating and the electromagnetic valve V is closed. In FIGURE 2 this condition is shown at the time 3 t When the timer U closes the switch ul at the predetermined time t2 the following operations take place. The relay b has its winding energized and then the glow body G is connected to the battery E by the switch [21 and the pump P is connected to the battery E by the switch b2. The relay-c is also energized and'thus the fan blower M and the electromagnetic valve V are connected inseries by the switch c1. At the time t;, the glow body G has been heated and the thermostatic switch T1 is then closed, relay. a is energized and the relay b is deenergiZed the glow body G is disconnected andthe seriesconnected fan blower M and the electromagnetic valve V are via the switch a1 connected to the battery E and the fan blower M starts rotating and the electromagnetic valve V opens. The pump P continues to operate asit is now connected to the battery E via the switches [13 and a1. Whenthe heatingmedium (the air) at the time n, has attained a predeterminedmaximum temperature the thermostatic switch T2 opens and the relay c is de-energized. and. the electromagnetic valve V closescutting off the fuel supply to the combustion chamber. The fan blower M continues to operate as it is now connected to the.battery.E by the switches c2 and a1. At the time 1 the thermostatic switch T1 has cooled down and opens.

and the relay a is thusde-energized and the fan blower M and the pump P will stop. At the time t the temperature of the heating medium has decreased so much that the thermostatic switch T2 closes and thereby the relay b is energized and the glow body G and the pump P are connectedto the battery, and the relay 0 is also energized and thus the fan blower M and the electromagnetic valve V are again connected in series. At the time t, the thermostatic switch T1 has again attained such a high temperature that it closes and the described sequence is repeated beginning from the time and is repeated period-.

ically as long asthe timer U holds the switch ul closed oruntil the battery E is manuallydisconnected.

From the .abovedescription of the operation it follows that the fan blower M when starting always is connected in series with the electromagnetic valve V, and the winding in the lastnamed electromagnetic valve is thus passedby-the high current which the fan blower takes when starting and the valve will. consequently. operate very quickly and reliably. When the fan blower is in its normal operating condition it takes a much smaller current but the electromagneticvalve V is dimensioned in such a way that the normal operating current for the fan blowor is sulficient for holding the valve opened once it has been opened. It is also clear that the units in the device are connected to the battery only during such time periods when it is necessary-that they operate and therefore the energy taken from the battery is a minimum. If during.

the cooling downperiod the timer U closes its switch 111 when the fan blower M is still rotating and the electromagnetic valve V is closed the valve is not opened because the current is too small. This small current depends on the counter set up by the still rotating fan blower M.

It is obvious to a person versed in the art that there are many modifications possible without departing from the spirit of invention. It is for instance possible to have the moving contact in the relay a consisting of the thermostatic switch T1, in other words the relay a is not absolutely necessary for the operation of the device. It would also be possible to substitute for the switches 01 and 02 a switch connected in parallel to the electromagnetic valve V. The embodiment shown in the drawing has however in practice beenfound to'very eifective and reliable.

I claim:

1. In a vehicle heating system, air heating means including a combustion chamber for combustion of a volatile fuel therein, electrically operable pump means for supplying the fuel to said combustion chamber, solenoid valve means for controlling delivery of the fuel to said combustion chamber supplied by said pump means, electric resistance heating means disposed adjacent said combustion chamber adapted to ignite said fuel, fan means arranged todeliver unheated air and heated air from said' air heating means, a first thermostatic switch means adjacent said combustion chamber, a second thermostatic switch means remotely disposed from said first thermostatic switch means and adapted to respond to the temperature of said heated air, batterymeans having one end.

connected to ground and the other end adapted to be connected to said pump means, valve means, resistance heatin g means and fan means to supply electrical energy thereto, said fan means and valve means. being serially connected with respect to each other, and switchmeans operatively controlled by one of said thermostatic switch means when unheated to energize both said fan means and valve means and when heated to energize only said blower, and further switch means separately controlled by the heating of the other of said thermostatic switch means to de-energize said electrical resistance heating means.

2. In a vehicle heating system according to claim 1 in which a timer means is interposedbetween saidsecond References Cited in the file of this patent UNITED STATES PATENTS 2,880,718 Ryder Apr. 7, 1959 Ray May 12, 1925 

1. IN A VEHICLE HEATING SYSTEM, AIR HEATING MEANS INCLUDING A COMBUSTION CHAMBER FOR COMBUSTION OF A VOLATILE FUEL THEREIN, ELECTRICALLY OPERABLE PUMP MEANS FOR SUPPLYING THE FUEL TO SAID COMBUSTION CHAMBER, SOLENOID VALVE MEANS FOR CONTROLLING DELIVERY OF THE FUEL TO SAID COMBUSTION CHAMBER SUPPLIED BY SAID PUMP MEANS, ELECTRIC RESISTANCE HEATING MEANS DISPOSED ADJACENT SAID COMBUSTION CHAMBER ADAPTED TO IGNITE SAID FUEL, FAN MEANS ARRANGED TO DELIVER UNHEATED AIR AND HEATED AIR FROM SAID AIR HEATING MEANS, A FIRST THERMOSTATIC SWITCH MEANS ADJACENT SAID COMBUSTION CHAMBER, A SECOND THERMOSTATIC SWITCH MEANS REMOTELY DISPOSED FROM SAID FIRST THERMOSTATIC SWITCH MEANS AND ADAPTED TO RESPOND TO THE TEMPERATURE OF SAID HEATED AIR, BATTERY MEANS HAVING ONE END CONNECTED TO GROUND AND THE OTHER END ADAPTED TO BE CONNECTED TO SAID PUMP MEANS, VALVE MEANS, RESISTANCE HEATING MEANS AND FAN MEANS TO SUPPLY ELECTRICAL ENERGY THERETO, SAID FAN MEANS AND VALVE MEANS BEING SERIALLY CONNECTED WITH RESPECT TO EACH OTHER, AND SWITCH MEANS OPERATIVELY CONTROLLED BY ONE OF SAID THERMOSTATIC SWITCH MEANS WHEN UNHEATED TO ENERGIZE BOTH SAID FAN MEANS AND VALVE MEANS AND WHEN HEATED TO ENERGIZE ONLY SAID BLOWER, AND FURTHER SWITCH MEANS SEPARATELY CONTROLLED BY THE HEATING OF THE OTHER OF SAID THERMOSTATIC SWITCH MEANS TO DE-ENERGIZE SAID ELECTRICAL RESISTANCE HEATING MEANS. 